Glenohumeral component for a shoulder prosthesis, and shoulder prosthesis comprising such a glenohumeral component

ABSTRACT

The glenohumeral component of the invention comprises a first side and a second side, which are opposite each other and which, in an implanted state in which the glenohumeral component is free-floating with respect to a humerus and a glenoid of a human shoulder, are in contact respectively with an end portion of the humerus and with a glenoid component intended to be secured to the glenoid. The first side of the glenohumeral component includes a convex articular surface that is designed to articulate with a concave bone surface prepared within the end portion of the humerus. The second side of the glenohumeral component includes a concave articular surface that is designed to articulate with a convex articular surface of the glenoid component. The corresponding shoulder prosthesis is thus reversed. Moreover, the articular interface between the glenoid component, which is secured to the glenoid, and the rest of the prosthesis has double mobility, which provides a greater range of motion between the glenoid and the humerus.

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 C.F.R. § 1.57.U.S. patent application Ser. No. 15/828,940, filed Dec. 1, 2017, nowU.S. Pat. No. 10,695,186, is hereby incorporated by reference herein inits entirety.

The present invention concerns a glenohumeral component for a shoulderprosthesis. The invention also concerns a shoulder prosthesis comprisingsuch a glenohumeral component.

In a healthy human shoulder, the head of the humerus, which is generallyball-shaped, and the glenoid cavity of the scapula articulate with eachother and form a ball-and-socket joint. Total shoulder arthroplasty is acommon treatment for shoulder pain resulting from arthritis or injuryand leads to replace the ball-and-socket joint by a shoulder orthopedicprosthesis.

Such a shoulder prosthesis generally includes both a glenoid implant tobe fixedly implanted at the glenoid of the scapula and a humeral implantto be fixedly implanted at the head of the humerus, the glenoid implantand the humeral implant being designed to articulate directly with eachother.

The invention focuses on another type of shoulder prosthesis, in whichthe humeral implant to be fixedly secured to the humerus is replacedwith a free-floating glenohumeral component, as proposed in US2011/0098822. As this free-floating glenohumeral component freelyarticulates with a concave bone surface that is prepared within an endportion of the humerus, US 2011/0098822 describes the glenohumeralcomponent as corresponding to an interpositionnal implant which hasnecessarily a sphere or ball shape so as to freely revolve on itselfbetween the aforesaid concave bone surface and either a concaveprosthetic surface of a glenoid component or a concave bone surface ofthe glenoid.

One of the goals of the present invention is to propose an improvedglenohumeral component that in particular is not limited to a sphericalshape.

To this end, one object of the invention is a glenohumeral component fora shoulder prosthesis, comprising a first side and a second side, whichare opposite each other and which, in an implanted state in which theglenohumeral component is free-floating with respect to a humerus and aglenoid of a human shoulder, are in contact respectively with an endportion of the humerus and with a glenoid component intended to besecured to the glenoid, wherein the first side of the glenohumeralcomponent includes a convex articular surface that is designed toarticulate with a concave bone surface prepared within the end portionof the humerus, characterized in that the second side of theglenohumeral component includes a concave articular surface that isdesigned to articulate with a convex articular surface of the glenoidcomponent.

Another object of the invention is a shoulder prosthesis, comprising:

-   -   a glenohumeral component as defined above, and    -   a glenoid component, which is designed to be secured to a human        glenoid and which has a convex articular surface with which the        concave articular surface of the glenohumeral component        articulates.

Thanks to the invention, the shoulder prosthesis is reversed, in thesense that the natural anatomy of the ball-and-socket joint of theshoulder is reversed. In that way, the articular interface between theglenoid component, which is secured to the glenoid, and the rest of theprosthesis is lateralized and lowered with respect to the scapula, whichgives the possibility of increasing the lever arm of the deltoid. Thisreversed prosthesis is therefore particularly indicated when the cuff ofthe patient is highly damaged, or even torn, partially or completely.Moreover, the aforesaid articular interface has double mobility, in thesense that the glenohumeral component of the invention remains mobileboth with respect to the glenoid, that fixedly bears the glenoidcomponent, and with respect to the humerus, that bears no fixedprosthetic component: this double mobility between the glenoid and thehumerus provides a greater range of motion between the glenoid and thehumerus. Besides, as the shoulder prosthesis of the invention does notinclude a prosthetic humeral component, there is no need to secure anyprosthetic component to the humerus, which avoids loosening of thesecurement of such a humeral component.

According to additional advantageous features of the glenohumeralcomponent and of the shoulder prosthesis:

-   -   the glenoid component comprises a glenosphere;    -   the glenohumeral component is in one piece on which are defined        both the convex and concave articular surfaces of the        glenohumeral component;    -   the glenohumeral component comprises a first piece, on which is        defined the convex articular surface of the glenohumeral        component, and a second piece, on which is defined the concave        articular surface of the glenohumeral component, the first piece        and the second piece being separate and being fixedly assembled        together;    -   the glenohumeral component comprises at least one third piece        that is fixedly interposed between the first and second pieces;    -   the convex articular surface of the glenohumeral component is        defined on a ceramic part of the glenohumeral component;    -   the convex articular surface of the glenohumeral component is        defined on a metal part of the glenohumeral component;    -   the concave articular surface of the glenohumeral component is        defined on a polymeric part of the glenohumeral component, and        the convex articular surface of the glenoid component is defined        on a ceramic part of the glenoid component;    -   the concave articular surface of the glenohumeral component is        defined on a polymeric part of the glenohumeral component, and        the convex articular surface of the glenoid component is defined        on a metal part of the glenoid component;    -   the concave articular surface of the glenohumeral component is        defined on a ceramic part of the glenohumeral component, and the        convex articular surface of the glenoid component is defined on        a polymeric part of the glenoid component;    -   the concave articular surface of the glenohumeral component is        defined on a metal part of the glenohumeral component, and the        convex articular surface of the glenoid component is defined on        a polymeric part of the glenoid component;    -   the concave articular surface of the glenohumeral component is        defined on a ceramic part of the glenohumeral component, and the        convex articular surface of the glenoid component is defined on        a ceramic part of the glenoid component;    -   the ceramic part of the glenohumeral component and/or the        ceramic part of the glenoid component are made of pyrocarbon;    -   the glenohumeral component includes a peripheral flange designed        to abut against an edge of the end portion of the humerus, the        edge bordering the bone surface, so as to limit range of        articulation between the glenohumeral component and the humerus.

Embodiments of the invention will be better understood from reading thedescription which will follow, which is given solely by way of exampleand with reference to the drawings in which:

FIG. 1 is an elevational view of a shoulder prosthesis that is implantedat a human shoulder;

FIG. 2 is an elevational view of a glenohumeral component of theshoulder prosthesis of FIG. 1, this glenohumeral component being shownalone;

FIG. 3 corresponds to FIG. 1, in which the glenohumeral component andthe humerus of the shoulder are illustrated in cross-section;

FIG. 4 is a cross-sectional view of a variant of the glenohumeralcomponent of the shoulder prosthesis of FIG. 1;

FIG. 5 is an elevational view of another embodiment of a shoulderprosthesis;

FIG. 6 is a view similar to FIG. 3, with the shoulder prosthesis of FIG.5; and

FIG. 7 is a cross-sectional view of a variant of the glenohumeralcomponent of the shoulder prosthesis of FIG. 5.

The FIGS. 1 and 3 show a human shoulder at which a humerus H and ascapula S are associated. The FIGS. 1 and 3 also show a shoulderprosthesis 1 which is implanted at the aforesaid shoulder so as to joina glenoid G of the scapula and a proximal humerus PH of the humerus H inan articulated manner.

The shoulder prosthesis 1 comprises a glenoid component 10 and aglenohumeral component 20 that is shown alone in FIG. 2.

In some embodiments as the one shown in the figures, the shoulderprosthesis 1 consists of the glenoid component 10 and the glenohumeralcomponent 20: in other words, the shoulder prosthesis 1 does not includeany component other than the glenoid component 10 and the glenohumeralcomponent 20.

The glenoid component 10 is designed to be secured to the glenoid G. Forthis purpose, the glenoid component 10 is provided with correspondinganchoring arrangements which are located at a side 10A of the glenoidcomponent, which faces the glenoid G when the glenoid component isimplanted. In practice, these anchoring arrangements of the glenoidcomponent 10, which are not detailed in the figures, are known per se.More generally, the embodiments of the anchoring arrangements of theglenoid component 10 are not limitative, provided these anchoringarrangements are operable intraoperatively by a surgeon to fixedlyfasten the glenoid component 10 to the glenoid G.

On a side 10B of the glenoid component 10, which is opposite to the side10A, the glenoid component 10 has an articular surface 11, which isconvex and which is provided to articulate with the glenohumeralcomponent 20 as explained later.

In some embodiments as the one shown in the figures, the convexarticular surface 11 is essentially spherical, being centered on an axisZ11, and is defined on a piece of the glenoid component 10, which formsa glenosphere 12.

In some embodiments, the glenosphere 12 or, more generally, the part ofthe glenoid component 10 on which the articular surface 11 is defined ismade of a hard material, typically made of metal, especially surgicalmetal alloys, or ceramic, especially pyrocarbon. In some otherembodiments, the glenosphere 12 or, more generally, the part of theglenoid component on which the articular surface 11 is defined is madeof a soft material, typically made of polymeric material.

Unlike the glenoid component 10, the glenohumeral component 20 is notprovided to be secured neither to the scapula S, especially the glenoidG thereof, nor to the humerus H, especially the proximal humerus PHthereof: as shown in the FIGS. 1 and 3, in the implanted state of theshoulder prosthesis 1, the glenohumeral component is free-floating withrespect to the scapula S, especially the glenoid thereof, and withrespect to the humerus H, especially the proximal humerus PH thereof.For this purpose, the glenohumeral component 20 is designed to beinterposed in a freely movable manner between the proximal humerus PHand the glenoid component 10 secured to the glenoid G.

Thus, the glenohumeral component 20 has a side 20A, which faces theproximal humerus PH when the shoulder prosthesis 1 is implanted andwhich is in direct contact with an end portion PH1 of the proximalhumerus PH. And the glenohumeral component 20 has a side 20B, which isopposite to the side 20A and which is in direct contact with the glenoidcomponent 10 when the shoulder prosthesis 1 is implanted.

As shown by the FIGS. 2 and 3, the side 20A of the glenohumeralcomponent 20 includes a convex articular surface 21 that is designed toarticulate with a complementary concave bone surface PH2 of the endportion PH1 of the proximal humerus PH. If necessary after having partlyresected the end portion PH1 of the proximal humerus PH, the bonesurface PH2 is prepared within this end portion PH1 before putting inplace the glenohumeral component 20 upon implantation of the shoulderprosthesis 1. The preparation and the constituent elements of the bonesurface PH2 are not limitative, provided the bone surface PH2 is shapedas a recessed socket into the end portion PH1 of the proximal humerus PHand the bone surface PH2 is defined by osseous material, either naturalor synthetic. Some embodiments of the bone surface PH2 are given forexample in US 2011/0098822 that is incorporated therein by reference.

In some embodiments as the one shown in the FIGS. 1 to 3, the convexarticular surface 21 is essentially spherical and is centered on an axisZ21.

When the shoulder prosthesis 1 is implanted, the convex articularsurface 21 and the concave bone surface PH2 are in direct contact so asto freely articulate one with respect to the other, especially somewhatin the manner of a ball joint. Thus, the convex articular surface 21 andthe concave bone surface PH2 freely tilt one with respect to one anotherboth in the cross-sectional plane of FIG. 3, as indicated by an arrow T1on FIG. 3, and in all the other geometric planes containing a centralgeometrical axis of the bone surface PH2.

In some embodiments as the one shown in the FIGS. 1 to 3, thearticulation between the glenohumeral component 20 and the proximalhumerus H, which results from the above-described cooperation betweenthe convex articular surface 21 and the concave bone surface PH2, has arange which may be limited, especially in order to prevent any unwanteddisengagement between the articular surface 21 and the bone surface PH2.For this purpose, the side 20A of the glenohumeral component 20 isprovided with a peripheral flange 22 which is designed to abut againstthe end portion PH1 of the proximal humerus PH, more precisely to abutagainst an edge PH3 of this end portion PH1, which borders the concavebone surface PH2. As shown for example for the articulationconfiguration of FIG. 3, this flange 22 mechanically interferes with alower portion of the edge PH3 so as to limit the range of tiltingbetween the glenohumeral component 20 and the proximal humerus PH in thecross-sectional plane of FIG. 3.

As shown by the FIG. 3, the side 20B of the glenohumeral component 20includes a concave articular surface 23 that is complementary to theconvex articular surface 11 of the glenoid component 10 and that is thusdesigned to articulate with this articular surface 11 when the shoulderprosthesis 1 is implanted.

In some embodiments as the one shown in the FIGS. 1 to 3, the concavearticular surface 23 is essentially spherical and is centered on an axisZ23 which may be coincident with the axis Z21 of the convex articularsurface 21.

When the shoulder prosthesis 1 is implanted, the concave articularsurface 23 of the glenohumeral component 20 and the convex articularsurface 11 of the glenoid component 10 are in direct contact so as tofreely articulate one with respect to the other, especially somewhat inthe manner of a ball joint. In some embodiments as the one shown in theFIGS. 1 to 3, the type of articulation between the articular surfaces 11and 23 is similar or even identical to the type of articulation betweenthe articular surface 21 and the bone surface PH2. Thus, the articularsurface 11 and 23 freely tilt one with respect to the other both in thecross-sectional plane of FIG. 3, as indicated by an arrow T2 on FIG. 3,and in all the other geometric planes containing a central geometricaxis of the articular surface 11, especially the axis Z11.

It will be understood that in use, a double mobility is operable betweenthe glenoid component 10, that is fixedly fastened to the glenoid G, andthe proximal humerus PH: a first mobility is operated by cooperationbetween the articular surface 21 and the bone surface PH2 and a secondmobility is operated by cooperation between the articular surfaces 11and 23. According to the various movements of the shoulder provided withthe shoulder prosthesis 1, one and/or the other of these first andsecond mobilities are more or less implemented, which provides a greaterrange of motion between the glenoid G and the proximal humerus PH.Furthermore, thanks to the fact that the opposed articular surfaces 21and 23 of the glenohumeral component 20 have respective curvatures thatare opposite, the aforesaid double mobility remains stable in use, withthe advantage that the concavity of the articular surface 23 enables tocombine the glenohumeral component 20 with a reversed glenoid componentas the glenoid component 10, in the sense that unlike a natural glenoid,the glenoid G provided with the glenoid component 10 has a convex shapeat the articular surface 11: compared to a natural glenoid, thearticulation between the glenoid G, provided with the glenoid component10, and the glenohumeral component 20 is lateralized and lowered withrespect to the scapula S. In this regard, the shoulder prosthesis 1 canbe considered as a reversed shoulder prosthesis with all thecorresponding functional advantages. That being said, the reversedshoulder prosthesis 1 has, as a specific aspect, no prosthetic humeralcomponent which would be fixedly fastened to the proximal humerus PH,since the glenohumeral component 20 remains free-floating with respectto the proximal humerus P: there is no need to secure any suchprosthetic component to the humerus H, which avoids the risk that such aprosthetic component separates from the humerus in an uncontrolledmanner as a result of high loads transmitted therethrough to thehumerus.

In some embodiments as the one shown in the FIGS. 1 to 3, theglenohumeral component 20 is made in one piece on which both articularsurfaces 21 and 23 are defined.

It follows that this one-piece glenohumeral component 20 is preferablymade of a hard material, typically made of metal, especially surgicalmetal alloys, or ceramic, especially pyrocarbon: such a hard materialprovides a good articular behavior with respect to the osseous materialof the bone surface PH2 of the proximal humerus PH. In that case, theglenosphere 12 or, more generally, the part of the glenoid component 10on which the articular surface 11 is defined may advantageously be madeof a soft material, typically polymeric material. That being said, insome embodiments, both components 20 and 10 may be each made of a hardmaterial, ceramic and ceramic for example.

Alternatively, the one-piece glenohumeral component 20 is made of a softmaterial, typically polymeric material; in that case, the glenosphere 12or, more generally, the part of the glenoid component 10 on which thearticular surface 11 is defined is made of a hard material, typicallymetal, especially surgical metal alloys, or ceramic, especiallypyrocarbon.

Turning now to the FIG. 4, a variant of the glenohumeral component 20 isconsidered, being labelled 20′. This glenohumeral component 20′ isidentical to the glenohumeral component 20 of the FIGS. 1 to 3, exceptthat the glenohumeral component 20′ does not have a flange similar tothe flange 22.

Turning now to the FIGS. 5 and 6, a shoulder prosthesis 101 isconsidered as an alternative embodiment for the shoulder prosthesis 1 ofthe FIGS. 1 to 3. The shoulder prosthesis 101 comprises or even consistsof both a glenoid component, which is identical to the glenoid component10 of the shoulder prosthesis 1 and which is therefore labelled 10 forthe shoulder prosthesis 101, and a glenohumeral component 120. Withrespect to the proximal humerus PH and the glenoid component 10, theglenohumeral component 120 is functionally similar to the glenohumeralcomponent 20: thus, two opposed sides 120A and 120B of the glenohumeralcomponent 120 respectively include a convex articular surface 121 forarticulating with the bone surface PH2 prepared within the end portionPH1 of the proximal humerus PH and a concave articular surface 123 forarticulating with the articular surface 11 of the glenoid component,while having the glenohumeral component 120 that is free-floating withrespect to the humerus H and the scapula S.

The glenohumeral component 120 differs from the glenohumeral component20 by its constitutive structure, in the sense that unlike being made inone piece, the glenohumeral component 120 comprises two distinct pieces120.1 and 120.2. The piece 120.1 defines the convex articular surface121 whereas the piece 120.2 defines the concave articular surface 123.In use, the two separate pieces 120.1 and 120.2 are fixedly assembledtogether. In practice, the means for fixedly assembling the pieces 120.1and 120.2 are not limitative, any appropriate embodiment, known per se,being possible for these means.

The two pieces structure of the glenohumeral component 120 mayadvantageously use to provide two different materials for the pieces120.1 and 120.2 respectively. Thus, in some embodiments, the piece 120.1may be made of a hard material, typically made of metal, especiallysurgical metal alloys, or ceramic, especially pyrocarbon, whereas thepiece 120.2 may be made of a soft material, typically made of polymericmaterial, being noted that in that case, the glenosphere 12 or, moregenerally, the part of the glenoid component 10 on which the articularsurface 11 is defined is preferably made of a hard material, typicallymade of metal or ceramic.

Alternatively, the piece 120.1 may be made of a soft material whereasthe piece 120.2 may be made of a hard material.

In some embodiments as the one shown in the FIGS. 5 and 6, theglenohumeral component 120 consists of the two pieces 120.1 and 120.2and, if appropriate, added elements of the aforesaid means forassembling these two pieces together. That being said, in some otherembodiments, the glenohumeral component may include at least one thirdpiece that is distinct from the two pieces 120.1 and 120.2: this thirdpiece is fixedly interposed between the pieces 120.1 and 120.2, whichmay facilitate the combination of the pieces 120.1 and 120.2 when theselatter are difficult to directly assemble together.

Turning now to the FIG. 7, a variant for the glenohumeral component 120is considered, being labelled 120′. The glenohumeral component 120′ isidentical to the glenohumeral component 120 of the FIGS. 5 and 6, exceptthat the glenohumeral component 120′ is provided with a peripheralflange 122′ which is functionally similar to the flange 22 of theglenohumeral component 20.

In some embodiments, as the one shown in the FIG. 7, the flange 122′belongs to a piece 120.1′ of the glenohumeral component 120′, which issimilar to the piece 120.1. In some other embodiments, a piece 120.2′ ofthe glenohumeral component 120′, which is similar to the piece 120.2,includes the flange 122′.

The invention claimed is:
 1. A method of implanting a reversed shoulderprosthesis, the method comprising: securing a glenoid component having aconvex articular surface to a human glenoid; resecting a portion of aproximal end of a humerus of a human shoulder, thereby forming aresected bone surface; preparing the resected bone surface such that theresected bone surface comprises a concave bone surface; interposing aglenohumeral component between the glenoid component and the resectedbone surface such that a concave articular surface of the glenohumeralcomponent is placed in direct contact with and freely articulates withthe convex articular surface of the glenoid component and a convexarticular surface of the glenohumeral component is placed in directcontact with and freely articulates with the concave bone surface;wherein the interposed glenohumeral component remains free-floating withrespect to both the proximal end of the humerus and the glenoidcomponent.
 2. The method of claim 1, wherein interposing theglenohumeral component comprises positioning a peripheral flange of theglenohumeral component adjacent to a portion of the resected bonesurface such that a side of the peripheral flange facing the resectedbone surface contacts the resected bone surface at a limit of a range ofarticulation of the glenohumeral component relative to the proximal endof the humerus.
 3. The method of claim 2, wherein one piece of theglenohumeral component includes both the peripheral flange and theentirety of the convex articular surface of the glenohumeral component.4. The method of claim 2, wherein an external angle along the convexarticular surface of the glenohumeral component between opposed portionsof the peripheral flange is 180 degrees.
 5. The method of claim 1,wherein the method does not include securing any prosthetic articularcomponent to the humerus.
 6. The method of claim 1, wherein the glenoidcomponent comprises a glenosphere.